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In-Plane Rotation Mechanism of Curve Bridge under Seismic Response HUANG Ming-fei 2011, 30(6): 1265-1269.  DOI: 10.3969/j.issn.1674-0696.2011.06.01 Abstract ( )   PDF (347KB) ( )   Seismic response of superstructure would appear eoupling phenomenon in curve bridge.This phenomenon mainly includes transverse displacement and in·plane rotation.The rotation mechanism of earthquake action in chord direction is re- searched. Based on the analysis on the simplified single-span curve bridge and linear time-history，the in-plane rotation mechanism of curve bridge is studied，and different seismic responses with different curvature ratio are compared.The efect of the girder-abutment interaction on the in-plane rotation is discussed.Nonlinear time-history method is applied to calculate the seismic response with diferent curvature and diferent input direction.Finally，the most adverse input angle of earth- quake is determined. References | Related Articles | Metrics

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Seismic Performance of Circular Reinforced Concrete Bridge Columns(H)： Evaluation of Experimental Results LI Gui-qian， ZHENG Gang ，WANG Jun 2011, 30(6): 1270-1274.  DOI: 10.3969/j.issn.1674-0696.2011.06.02 Abstract ( )   PDF (719KB) ( )   According to the failure phenomenon and test data in the orthogonal quasi-static test，the characteristics of deform- ation and flexural strength of circular reinforced concrete bridge columns are studied.And the displacement ductility.effec- tive stiffness，stiffness degradation and capacity of accumulative energy dissipation to ultimate displacement state of bridge columns subjected to low-cyclic loading have been evaluated，so as to investigate the influence of factors such as shear-span ratio，axial-load ratio，and longitudinal reinforcemem ratio and spiral reinforcement ratio on ductility perform ance of bridge columns.Finally，some useful conclusions are found out for the ductile anti-seismic design of highway bridges. References | Related Articles | Metrics

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Impact of Tie-Down Cable on Main Girder of Multi-tower Cable-Stayed Bridge TANG Ping-jian，WANG Hong，WANG Peng 2011, 30(6): 1275-1277.  DOI: 10.3969/j.issn.1674-0696.2011.06.03 Abstract ( )   PDF (296KB) ( )   Through the application of the calculation method of the conventional two towers cable-stayed bridge，the simplified static calculation formula of a structural system of multi-tower cable-stayed bridge with tie-down cables is got. Furthermore， a finite element analysis model is established. Taking different set locations of the tie-down cable as parameters，the impact of the tie-down cable layout on the force of main girder is analyzed. The results show that: setting up the tie-down cable can locally increase the axial force on the main girder，but reduce the moment correspondingly; and the bearing on the main beam is less affected by setting up the tie-down cable. References | Related Articles | Metrics

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Crack Mechanism and Performance Evaluation Method of Monolithic Reinforced Concrete Hollow Slab Bridge XU Jian-hong 2011, 30(6): 1278-1281.  DOI: 10.3969/j.issn.1674-0696.2011.06.04 Abstract ( )   PDF (268KB) ( )   Crack mechanism of reinforced concrete hollow slab bridge and its performance evaluation method are studied． A refined spatial solid model is established by ANSYS to investigate the crack mechanism of bridge under design loads． And then on the basis of the elastic analysis，the load test results are evaluated，with the consideration of the nonlinear performance of concrete material． The load test results are compared with the results got by rigid-connection slab and elastic linear finite method． The corrosion model of steel bar is introduced for the long term performance evaluation，and the time-dependent carrying capacity of the bridge is analyzed． The study results indicate that the horizontal deflection caused by the vehicles’eccentric load is the main cause of the longitudinal cracking of bridge． It is suggested that the nonlinear performance and corrosion should be included in the evaluation of hollow slab bridge． References | Related Articles | Metrics

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Allowance of Concrete Crack Width Based on Durability of Domestic and Overseas Code HE Hua，WU Hai-jun，GAO Yu，LU Ping 2011, 30(6): 1282-1286.  DOI: 10.3969/j.issn.1674-0696.2011.06.05 Abstract ( )   PDF (213KB) ( )   Crack limit values home and abroad are analyzed and compared，and then the connotation and characteristics of the allowance width of crack are pointed out respectively． It is proposed that durability crack limit should take environment， steel，stress characteristic，component styles，crack position and construction feature into consideration． The crack limit range and relationships of concrete component and pre-stressed concrete component are concluded in alternate drying-wetting， no alternate drying-wetting and corrosion environment，which provides useful reference for allowance width of crack in concrete bridge constructor based on durability． References | Related Articles | Metrics

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Rapid Computation Method of Traverse Distribution Coefficients about Bridges with Big Wide-Span Ratio CHEN Qiang，MENG Yang-jun，ZHOU Xian-yan 2011, 30(6): 1287-1289.  DOI: 10.3969/j.issn.1674-0696.2011.06.06 Abstract ( )   PDF (542KB) ( )   Based on the analogy orthotropic plate principle，traverse distribution function under the design load is theoretically deduced and the piecewise function to fitting curves is used． This computation method has greatly improved not only the computational efficiency but also the precision． Furthermore，the deduced transverse distribution expression is also available to be applied in the modular programming，which has laid a foundation work for the engineering software analysis． References | Related Articles | Metrics

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FEM Analysis on Fire in Box-Girder of the Gaojia Garden Bridge SHI Ling-li，ZHANG Ben-niu ，WANG Jia-lin ，ZHANG Xu 2011, 30(6): 1290-1293.  DOI: 10.3969/j.issn.1674-0696.2011.06.07 Abstract ( )   PDF (290KB) ( )   On September 3，2009，the box girder of Gaojia Garden Bridge caught a fire during the maintenance and rein- forcement． Based on the theory and algorithm of Heat Transfer ， the model of Gaojia Garden Bridge box girder with varying section has been established by use of the Finite Element Method and ABAQUS finite element software．The resuits got bv the model are compared with those got in the monitoring．The comparison shows that the calculated deflection values basica1- ly match the measured ones，which has a referential value for the evaluation on bridge structures condittion References | Related Articles | Metrics

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Damage Analysis on Collision between Over-High Truck and Bridge Based on FEM BI Chen-hua，ZHANG Yong-shui 2011, 30(6): 1294-1297.  DOI: 10.3969/j.issn.1674-0696.2011.06.08 Abstract ( )   PDF (835KB) ( )   Based on finite element analysis software ABAQUS，the collision between over-high truck and bridge is simulated， which considers the co-bearing of steel and concrete．as well as the material nonlinearity of concrete．According to the colli- sion caused by over-high truck at different speed，the collision mechanism of Car-bridge and the damage of bridge due to the collision are researched．Analysis shows that the higher the vehicle speed，the larger the stress of the girder，and the shorter the time needed to amount to the maximum stress；the damage of girder is very large due to the collision，especially the ten- sion damage，and the damage mainly occurs in the first half of the collision． References | Related Articles | Metrics

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Surrounding Rock Structures and Mountain Stability of Chadong Bank of the Aizhai Suspension Bridge PENG Jian-guo，ZHANG Qi-hua，HU Hui-hua，LONG Shu-wei 2011, 30(6): 1298-1302.  DOI: 10.3969/j.issn.1674-0696.2011.06.09 Abstract ( )   PDF (326KB) ( )   Geological defects and stability problems of Chadong bank of Aizhai Super Suspension Bridge exposed in the excavation are investigated and analyzed． Based on these，by means of three-dimensional numerical analysis，surrounding rock stability of tunnel-type anchorage，caber tower and highway tunnel，as well as mountain stability are analyzed in different construction stages，including the condition stage after the rock mass excavation and the exertion of design load． Rock mass reinforcement is designed based on the results of numerical analysis． Analysis results show that stability problems focus on the stability of abutment slope，the influence of the design load on stability of rock mass is very limited，and mutual effects between structures are also limited． Tunnel-type anchorage can generate very huge pull-resistance force，which is caused by surrounding rock mass’‘squeezing effect’and the bearing capacity of tunnel-type anchorage may be underestimated severely． References | Related Articles | Metrics

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Interaction between Integral Cantilever Structure and Rock-Soil LIU Chen-guang，ZHOU Zhi-xiang，MAO Jiu-qun 2011, 30(6): 1303-1305.  DOI: 10.3969/j.issn.1674-0696.2011.06.10 Abstract ( )   PDF (582KB) ( )   A new structure of widening mountain road with integral cantilever(ICS)is introduced．In order to analyze the response of rock．soil to load．numerical simulation is done by making use of the finite software；and then a simplified calcu- lation method is brought forward．Furthermore．a calculation program is compiled by visual C++，which is suitable for this strueture．Finallv．the interaction between integral cantilever structure and rock-soil is researched by using the calculation Drogram．The resuhs show that the structure stress is affected by diferent soil；it is economic to choose old landfill and grav- el soil in practical engineering． References | Related Articles | Metrics

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Sensitivity Analysis on Error in Cantilever Erection of Curve Prestressed Continuous Girder Bridge ZHOU Man ，WANG Fu-min ，WANG Peng ，SONG Jun ，ZHAO Yan-lei ，LIU jing 2011, 30(6): 1306-1310.  DOI: 10.3969/j.issn.1674-0696.2011.06.11 Abstract ( )   PDF (341KB) ( )   A 3-dimensional finite element calculating model is established for the main bridge of Xiazhang to North Branch of the south approach spans the third joint by using software Midas Civil．The influence of various factors on the large curvature continuous bridge alignment and internal forces is researched and these factors include the height difference of vertical beam，beam of negative height of vertical，horizontal axis deviation，stand deviation ， and the unevenness of the effective prestress．The results show that the beam height difference and the prestressed cross-section unevenness have severe influence on the girder deflection and stress；the top of the negative beam height，axis deviation ， and the unevenness degrees of prestressed beam is followed in order．And the infl uence of bearing deviation on girder deflection and stress can almost be ignored． References | Related Articles | Metrics

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Control Technology of Half-Through CFST Arch Bridge Construction WEI Li-dong，XIANG Zhong-fu，ZHAN Ning 2011, 30(6): 1311-1313.  DOI: 10.3969/j.issn.1674-0696.2011.06.12 Abstract ( )   PDF (280KB) ( )   As the main bridge structure is of complexity，hish technology content and construction dificuhicuhy，the construction of concrete．filled steel tubular tie．bar arch bridge requires construction control in the whole process of construction． Though the monitoring of carriageway edge beams lifted by hoisting cable hoisting system，machine and car lanes lifted by gantry crone an d sidewalk beams lifted by the cran e hoisting，it is ensured that the bridge alignment meets the design requirements after completion and the structure stress is rational，which provides a reference for the similar bridge construction monitoring． References | Related Articles | Metrics

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Comparative Experiment Analysis for Light Distribution of Highway Tunnel JI Jia-jun ，WANG Xiao-wen，CHEN Jian-zhong 2011, 30(6): 1314-1317.  DOI: 10.3969/j.issn.1674-0696.2011.06.13 Abstract ( )   PDF (273KB) ( )   Taking the middle period of lighting as the research object，comparative experiments of 1：1 actual tunnel are carried out，which reveals the essence of economic distribution of light．The lighting distribution data of backlight lamps and lanterns and conventional ones with diferent spacing are analyzed，and the advantages and disadvantages of the two kinds of typical tunnel lighting lamps and lanterns in the design are obtained．A reasonable and economical solution for light distribution problem is proposed． References | Related Articles | Metrics

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Analysis on Inter-laminar Shear Stress of Composite Pavement YUAN Ming，LING Tian-qing，ZHANG Rui-zhuo，FANG Gang 2011, 30(6): 1318-1322.  DOI: 10.3969/j.issn.1674-0696.2011.06.14 Abstract ( )   PDF (440KB) ( )   The common disease of composite pavement is often in the form of interfacial shear slip damage．Firstly，typical cement concrete level layers，bonding layer，asphalt concrete top layer are selected as a whole layer．And then the compos． ite pavement interlayer maximum shear ，shear angle and the sensitivity for temperature，structure layer thickness，material modulus，driving load and SO on are calculated by using BISAR 3.0 program ．Results show that：the thickness of AC layer， the modulus of bonding layer，the traffic load have a significant effect on interlayer shear and shear angle．W hen the thick- ness of bonding layer changes from 6mm to 16mm，the interlayer maximum shear reduces by 48.85％ ，and shear angle re- duces by 11.29％ ．Meanwhile，the influence of the thickness of bonding layer on the inter-laminar shear stress and resist- anee pull force performance is analyzed compositely，which determ ines the reasonable thickness of adhesion is 3mm．Surf and fminsearch in MATLAB software are used as tools to draw 3D surface graph about interlayer shear，shear angle with the thickness of AC layer and the modulus of bonding layer；finally，non-linear optimization is carried out to fit out the function of the relationship among the above three． References | Related Articles | Metrics

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Experimental Investigation on Mechanical Characteristics of Steep Concrete Pavement YANG Xi-wu，GE Yun-qi 2011, 30(6): 1323-1326.  DOI: 10.3969/j.issn.1674-0696.2011.06.15 Abstract ( )   PDF (840KB) ( )   The stress of bottom and surface of concrete plate were tested to proof influence of slope on the stress of plate and the finite element method is applied to analyse the tested plates and the calculation results are compared with the test results． The results show that with the longitudinal route slope increasing the biggest tensile stress in the bottom is decreases and the shear stress is increases，at same longitudinal route slope condition ，the tensile stress at the bottom of board is the biggest． Based on the changing law of the concrete board stress with slope，the slope value of need to consider the impact of longitudinal route slope on stress in pavement design is suggested in the paper． References | Related Articles | Metrics

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Influence of M eteorological Elements on Temperature Field of Asphalt Pavement ZHANG Nai-ji ，LIANG Nai-xing ，ZHU Ya-ping 2011, 30(6): 1327-1330.  DOI: 10.3969/j.issn.1674-0696.2011.06.16 Abstract ( )   PDF (268KB) ( )   Solar radiation，air temperature，sunshine duration and wind velocity on the impact of asphalt pavement temperature have been analyzed，and then the corresponding analog functions and solutions are put forward．Contrastive analysis is carried out on the basis of measured meteorological data．The results show tllat the applied simulation。calculation function Can well imitate the change of meteorological elements，and it has high precision，which prepares conditions for accurate prediction of the pavement temperature field． References | Related Articles | Metrics

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Road Performance of High Modulus Asphalt Concrete Additive Calcium Sulfate Whisker WANG Xiu-shan 2011, 30(6): 1331-1334.  DOI: 10.3969/j.issn.1674-0696.2011.06.17 Abstract ( )   PDF (175KB) ( )   The application effect of high modulus asphalt concrete additive calcium sulfate whisker in the asphalt mixtures is studied on the basis of road performance． Three mixtures are involved in the experiment and a comparative study of test results are carried out． The results show that the high modulus of asphalt mixture which is modified by calcium sulfate whisker can effectively improve the high temperature stability，water stability and anti-fatigue performance; at the same time，it doesn’t decrease the mixture low temperature performance． Finally，the feasibility analysis shows that: the road performance of calcium whisker high modulus asphalt concrete pavement is good and it has high economic and social benefits． References | Related Articles | Metrics

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Image Segmentation and Its Effect of Asphalt Mixtures Using Computed Tomography Images Method LIU Jia-hui，LI Zhi 2011, 30(6): 1335-1338.  DOI: 10.3969/j.issn.1674-0696.2011.06.18 Abstract ( )   PDF (607KB) ( )   A circular blocking method is designed on the basis of OTSU method． This method is proposed to resolve the technical problems of segmentation between target aggregate particles and asphalt mortar background in CT image gray of pavement core samples without obvious bimodal． Moreover，evaluation studies are carried out through designing experiments emphatically from image segmentation． The results show that the quality of image segmentation has been improved significantly by using circular blocking method and OTSU method together． Furthermore，comparing with the optimal threshold method ( Manual) ，the accuracy of the circular block OTSU method is evaluated quantitatively by using area ratio of aggregate particles as an indicator，and the result turns out to be ideal． References | Related Articles | Metrics

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Experimental Study on Influence of Polyacrylamide on Properties of Cement Paste ZHANG Chang-qing ，CAO Zhi-yu ，ZHANG Guang-guo， HUANG Zhi-yuan ，JIN Wen-cheng ，YI Chang-xing 2011, 30(6): 1339-1343.  DOI: 10.3969/j.issn.1674-0696.2011.06.19 Abstract ( )   PDF (932KB) ( )   Thickening agent is one of admixtures used for preparation of self-compacting concrete(SCC)．This research chose polyacrylamide(PAM)as thickener．Cement mixed with PAM，Water content of the Standard consistency of cement increases and the setting time of cement paste prolongs with the dosage of PAM．With PAM suitable dosage of 0.1‰～0.5‰，the yield stress(τ0)of cement is minimum and the viscosity(η)is higher．When PAM is less than 0.5‰，PAM could reduces the shrinkage of hardened cement paste．PAM's impacting on the electrical resistivity of cement paste reflects the competition between the cross-linking and hydrolysis of PAM．SEM shows that PAM introduces closed air bubbles into cement paste and increases the hydration products’compacting，so strength of cement couldn't show significant variation when the PAM dosage is increased． References | Related Articles | Metrics

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Pavement Performance of Lime-Fly Ash Slag Mixture ZHANG Hai-bin，YU Ming-ming，LI Xiao-jian 2011, 30(6): 1344-1346.  DOI: 10.3969/j.issn.1674-0696.2011.06.20 Abstract ( )   PDF (172KB) ( )   In order to study the pavement performance of lime-fly ash slag，the frost resistance，dry-shrinkage property， scour resistance experiments of 3 kinds of lime-fly ash slag mixtures are performed． The experiment shows that the antifreezing and thawing performance of lime-fly ash slag mixture is better than that of lime-fly ash broken stone; the shrinkage coefficient is much less than that of lime-fly ash broken stone with the same mix proportion． And the frost resistance，dryshrinkage property，scour resistance of lime-fly ash slag is best when the mixture proportion ratio is 5∶15∶80． References | Related Articles | Metrics

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Numerical Simulation of the Stability of Expansive Soils Embankm ent Reinforced by Geogrid WEI Bing-xu 2011, 30(6): 1347-1352.  DOI: 10.3969/j.issn.1674-0696.2011.06.21 Abstract ( )   PDF (763KB) ( )   Strength and stress．moisture content．strain relationship of unsaturated soil is established by introduction of mois- ture content．W ith the consideration of some key factors，such as the interaction between geogrids and expan sive soil，ex- pansion which is caused by absorbing water and softening characteristics，a new stability calculation method is proposed to calculate the stability of expansive soils embankment reinforced by geogrid．A case study shows that the approach is reasonable． Moisture ratio which Can be easily gained in geotechnical engineering is introduced into the calculation approach of sta- bility for expansive soil embankment reinforced by geogrid，which avoids the complex theoretical system of unsaturated soil． The characteristics of slope and unsaturated soil are indirectly realized by the relationship that kinds of soil property parame- ters vary synchronously with moisture content．Therefore，the proposed method is an effective way to realize practical engi- neering purpose of theoretical achievements of unsaturated soil． References | Related Articles | Metrics

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Feature Analysis and Design Discussion for Reinforced Gabion Retaining Wall LIU Zhao-sheng，YAO Ling-kan，ZHU Hong-wei，LIU Min 2011, 30(6): 1353-1358.  DOI: 10.3969/j.issn.1674-0696.2011.06.22 Abstract ( )   PDF (584KB) ( )   The properties of gabion mesh Role properties are examined by the indoor pull-out test，the dynamic features of reinforced gabion retaining wall analysis are studied through shaking table test，analyzing the destruction under seismic loading and the failure law of its ground breaking pressure，to find out the worst part of reinforced gabion retaining wall under seismic loading and provide Related measures for enforcing the wall． Geo-Studio software，using an artificial coupling finite element numerical simulation model，compares analytically the results of shaking table model test and the finite element numerical simulation with the same size，to further study the dynamic characteristics of reinforced gabion retaining wall，study reinforced gabion retaining wall system in the overall force system gabion retaining wall and the wall reinforcement effects． References | Related Articles | Metrics

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Influence of Intermittent Saturation on Mechanical Properties of Sandstone HE Ye，ZHAO Ming-jie，YANG Yan-ping ，LONG Teng-hui 2011, 30(6): 1359-1362.  DOI: 10.3969/j.issn.1674-0696.2011.06.23 Abstract ( )   PDF (303KB) ( )   Combining with field sampling and tri-axial test，and taking sandstone which is common in project for example， difierent saturation numbers are designed． Then intermittent saturation trial and mechanical index test are conducted． Through comparative analysis of mechanical index of sandstone under n~ural state and different saturation number，research about the change regularity on mechanical properties of sandstone before and after intermittent saturation is carried out．The results show that：with the increase of intermittent saturation numb er，the compressive strength，cohesion and internal fric- tion angle of sandstone all show a downward trend and their varying regularities probably conforin to an exponent curve． References | Related Articles | Metrics

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Flexibility Matrix in Stress Stain Relationships of Soil LU Xi，SHI Wei-cheng 2011, 30(6): 1363-1365.  DOI: 10.3969/j.issn.1674-0696.2011.06.24 Abstract ( )   PDF (188KB) ( )   It is demanded that the flexibility matrix have positive main diagonal elements and be diagonal dominant in stress strain relationships of soil．Through the study of the principal stress-expressed flexibility matrix，it is proved that the determinant of the flexibility matrix would be positive if the flexibility matrix satisfies the both conditions．Therefore it could be a method to estimate a constitutive model of soil whether the determinant of the flexibility matrix is positive or not．Finally，the plastic flexibility matrix of traditional elastoplastic models is studied．It is found that the determ inant of the plastic flexibility matrix based on traditional elastoplastic theory is equal to zero，SO the plastic flexibility matrix based on traditional elastoplastic theory could not be diagonal dominant．Consequently a traditional elastoplastic model has its limitation in the description of the mechanical properties of soils． References | Related Articles | Metrics

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Introduction of Service Area Planning and Designing in Taiwan Highway KONG Jia-wei，SUN Jia-si 2011, 30(6): 1366-1369.  DOI: 10.3969/j.issn.1674-0696.2011.06.25 Abstract ( )   PDF (307KB) ( )   Service area of highway is an essential part of highway project． On the one hand，it provides operation of highway with different kinds of services and facilities． On the other hand，it functions as an interior access of highway． That is why it has certain influence on the traffic of highway． On the basis of analyzing the layout and construction features of Taiwan Highway’s service area，a few planning thoughts which aim at the present issues of Chongqing’s highway are proposed． References | Related Articles | Metrics

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Bus Station Optimization M ethod Based on the Principle of Station Canceling and Station Combining LI Ying-shuai，YAO Hong-yun，QIN Lei 2011, 30(6): 1370-1374.  DOI: 10.3969/j.issn.1674-0696.2011.06.26 Abstract ( )   PDF (347KB) ( )   Bus-stop spacing optimization csl'l shorten the running time of single-route bus and improve the bus service leve1． Therefore，the bus passenger transport ability and optimum average bus-stop spacing are used as quantification index in bus- stop spacing optimization method．The conclusion of passenger flow demand assignment model is drawn by using the prinei． ple of distance distribution，which is on the basis of the combination of passenger flow demand and bus-stop spacing selee． tion．Lastly，256-bus in Changehun City is involved in the ease study．The case study has drawn a conclusion that the pro posed optimization principle has saved the passenger's time and improved the service level of regular single．route bus ，which is of certain practicality． References | Related Articles | Metrics

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Traffic Flow Simulation of Multi-lane Highway Bridge Based on Monte Carlo Method CHENG Gao ，LIU Yong-jian ，ZHANG Jun-guang ，YAO Zhi-gang 2011, 30(6): 1375-1378.  DOI: 10.3969/j.issn.1674-0696.2011.06.27 Abstract ( )   PDF (348KB) ( )   Through analyzing vehicles’measurement data，the distribution and parameters of traffic characteristics such as mode1 vehicles．vehicle weight and time headway etc．are determined．Samples are stochastically selected by the Monte Carlo method．and the MATI．AB is also program med．Finally，the free trafic flow is simulated，by which the vertical and horizontal distribution of the vehicle weight and axle load on bridge，and their changing conditions with time are obtained．In addition．three situations of lane coefficients of uniform ity are alSO discussed．The resuh of discussion iS that the axle load iS of multi．peak distribution．which has close peak values but different frequency． References | Related Articles | Metrics

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Distribution Characteristics of Nitrate Nitrogen and Nitrite Nitrogen in the Jiantan River Basin in the Three Gorges Reservoir Area LIU Xiang-chao ，LV Ping-yu ，WU Lin-jian ，GAO Wu 2011, 30(6): 1379-1383.  DOI: 10.3969/j.issn.1674-0696.2011.06.28 Abstract ( )   PDF (481KB) ( )   38 samples in surface water and 13 samples in drinking water wells in rural areas are collected in the Jiantan River in the Three Gorges Reservoir area during the low water period．Nitrate nitrogen and nitrite nitrogen in the samples are meas ured and analyzed to depict the distribution of nitrate and nitrite pollution in the studied basin．Correlativity analysis reveals the relationship between the nitrate nitrogen and the nitrite nitrogen level of the surface water samples in tbe study basin． Th e NO3-N is serious exceeded in rural drinking water wells along the Jiantan River Basin，and the importance of the safety of drinking well water in rural areas is proposed． References | Related Articles | Metrics

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Variety Characteristics of Sediment Size in Wanzhou-Lidu Reach during 135 － 139m Water Phase of the Three Gorges Reservoir YANG Sheng-fa，WANG Xiao，HU Jiang 2011, 30(6): 1384-1387.  DOI: 10.3969/j.issn.1674-0696.2011.06.29 Abstract ( )   PDF (327KB) ( )   From Jun. 2003 to Sep. 2006，the Three Ggorges Reservoir is running with the 135—139 m dispatching operation scheme． The scheme means the water level is 139m during low water season and 135m during flood season． The backwater end is located at Lidu in Fuling district，and the reach ever in back water is below Fengdu． Through analyzing the prototype observation data of the Three Gorges Reservoir，the variety characteristics and the gradation of sediment in this reach has been studied． The rule of sediment motion is obtained based on the analysis of sediment size in this reach，which could be a preliminary understanding of sediment motion rule in the Three Gorges Reservoir district． References | Related Articles | Metrics

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Goal Adjustment for Luxikou Waterway Regulation in the Yangtze River HU Xiao-qing 2011, 30(6): 1388-1391.  DOI: 10.3969/j.issn.1674-0696.2011.06.30 Abstract ( )   PDF (659KB) ( )   The thought of Luxikou waterway regulation is firsdy to make use of the current favourable opportunity．And the thought intends to improve the channel dimension and navigation conditions by taking advantage of the Xinzhou dam，Zhong． zhou branch revetment and Zhigang branch dredged channel engineering measures；the regulation also intends to realize the navigation between Zhigang and Zhonggang branches，and finally to make Zhigang branch as the main channe1．As the engi- neering is implemented in the drastic evolution period of Luxikou waterway，and is also influenced by the discharging water from the Three Gorges Reservoir，the target that Zhigang branch is used as the main channel is dificult to achieve；howev- er，Zhonggang branch is in a good condition．Analysis on the navigation conditions in the status and trends of Zhonggang branch is carried out，which determines that the regulation goal is adjusted to make the Zhonggang branch as the main navi- gable channe1．Therefore，the corresponding abolition of Zhigang branch dredged channel is carried out． References | Related Articles | Metrics

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Three-dimensional Modeling and C ++ Programming of Logarithmic Spiral Double Curved Arch Dam DU Qi-lu，DU Ting-na 2011, 30(6): 1392-1395.  DOI: 10.3969/j.issn.1674-0696.2011.06.31 Abstract ( )   PDF (203KB) ( )   Logarithmic hyperbolic arch dam stress condition is good，so it is increasingly applied into practical engineering． Based on the study of various geometric parameters of logarithmic hyperbolic arch dam，the numerical model of logarithmic hyperbolic arch dam is established． Three-dimensional entity simulation is completed in Auto-CAD by using C++ programming language programming． Three-dimensional entity mode provides accurate entity mode for the future finite element analysis of arch dam． References | Related Articles | Metrics

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Hydraulics Prototype Observation on Conveyance System of the Jinpanzi Power Station in Qujiang River LIU Ping-chang，ZHOU Jia-yu，WANG Zhao-bing，DING Shen-qi 2011, 30(6): 1396-1399.  DOI: 10.3969/j.issn.1674-0696.2011.06.32 Abstract ( )   PDF (372KB) ( )   In order to study the differences between the simulation tests and prototype tests on the high water head of lock，and accumulate further experience on the operation of high water head of lock in the same time，the hydraulic prototype observation on conveyance system of Jinpanzi Power Station in Qujiang River is carried out．Prototype obser- vation results show that the impoa，export of the lock and the gate house have a fine flow pattern；the gate indoor ship mooring force meets the regulatory requirements：the flow coeficients of chamber filling and draining of are 12％～ 16％ larger than those designed in the model，which basically accords to the results got in domestic and foreign study of water supply system．The sluice valve opening speed is much greater than the designed one and the one got by the sim- ulated model，therefore，its corridor suction pressure value exceeds the requirements of specifications．Finally，suggestions for improvement are proposed． References | Related Articles | Metrics

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Benefit Value Calculation Model of Ecological Restoration XU Lan ，ZHOU Fu-chun 2011, 30(6): 1400-1403.  DOI: 10.3969/j.issn.1674-0696.2011.06.33 Abstract ( )   PDF (386KB) ( )   Taking highway engineering as example，environmental space is divided into six aspects，including the water envi- ronment，soil environment，atmospheric environment，sound environment，biological environment and landscape environ- ment．Monetary efficiency value calculation model of ecological restoration is established，through various evaluation meth- ods，including the shadow engineering method，protective cost method，recovery ／reset cost method．Then the engineering data of case study are involved in the model，so the feasibility of the model is verified and evaluation results are obtained． The proposed model proves that environmental space will produce a great benefit value after the implementation of ecological restoration． References | Related Articles | Metrics

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Acquisition of Basin Characteristics of Drinking Water Sources in Lake Reservoirs ZHOU Ling，LIN Xiao-song，LIU Shu-jun，JIANG Tian-ming 2011, 30(6): 1404-1407.  DOI: 10.3969/j.issn.1674-0696.2011.06.34 Abstract ( )   PDF (688KB) ( )   Taking Shaba Reservoir of Liangping in Chongqing as research object and use the ArcGIS hydrologic analysis mod- el,the sub—watershed after the procedure iS divided and the data of the river network basin are collected and an alyzed．The analysis results indicate tIlat when the drainage area threshold amounts to 3000,the extracting river net is most close to the actual distribution of water system．On the basis of this relationship．13 sub-basins are divided．Moreover,according to a- nalysis 0n eonditions of land use．it is suggested that No．1～5 sub—watersheds around the reservoir are disturbed bv human ’ s activities，especially No．1 sub-watershed，which needs countermeasures to recover．The characteristics derived from the extraction of the lake type water source provide convenience for the management of watershed grading an d recovering，and provide a basis for environment protection of the drinking water source watershed at the same time． References | Related Articles | Metrics

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Review on Application of Statistical Downscaling Techniques in China HOU Bao-jian，WANG Miao-lin，FU Hua 2011, 30(6): 1408-1411.  DOI: 10.3969/j.issn.1674-0696.2011.06.35 Abstract ( )   PDF (159KB) ( )   The downscaling technique is useful for solving the problem of combining the atmospheric circulation model scenarios ( GCMs) and hydrological models． The main characteristics and background of downscaling method are analyzed． The classification of the advantages and disadvantages of each downscaling method are introduced． According to the application the statistical downscaling methods in different areas in recent years，the theory of statistical downscaling methods，application procedures and research progress are systematically discussed． Through comparative analysis，statistical downscaling method is superior to dynamical downscaling． And the shortages of the application of statistical downscaling need to be improved in the future，especially the shortages in the precipitation forecast． Finally，prospects of developing new downscaling techniques by combining statistical and dynamical downscaling techniques are pointed out． References | Related Articles | Metrics

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Test and Simulation of All-Wheel Steering System for Stabilized Soil Mixer MA Li-ying，GUI Shao-xiong，CAO Yuan-wen 2011, 30(6): 1412-1414.  DOI: 10.3969/j.issn.1674-0696.2011.06.36 Abstract ( )   PDF (232KB) ( )   Based on the analysis of the all-wheel steering test platform for stabilized soil mixer，a series of tests for each steering working condition are carried out． The transfer function of the system is determined，and Bode diagram is also drawn out． Meanwhile，the system is simulated dynamically by use of MATLAB/SIMULINK software． The research results show that the amplitude margins and phase margins of the steering system are respectively 13.4dB and 48.9°，which meets the stability reserve requirements of the steering system for stabilized soil mixer; the fast response speed and the stability of experimental system also meet the requirement; what's more，all-wheel steering decreases about 20% turning radius than 2 wheel steering does． References | Related Articles | Metrics

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Numerical Simulation of PCCI-DI Combustion Engine Fueled th DME(Ⅱ) LI Wei，WANG Wen ，HUANG Yong-cheng，WANG Ying 2011, 30(6): 1415-1419.  DOI: 10.3969/j.issn.1674-0696.2011.06.37 Abstract ( )   PDF (633KB) ( )   TAB breakage model is substituted by the WAVE broken mode1．PSR (Partially-Stirred-Reactor)combustion model with detailed chemical reaction mechanism is adopted in KIVA program，three dimensional numerical simulation of DME PCCI-DI combustion is carried out．The computation result call accurately reflect the characteristics of DME PCCI-DI combustion and various components density changing situations in the cylinder． References | Related Articles | Metrics

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Stability Analysis for a Vehicle Control System Based on a Spatial Previewed Driver Model JIANG Wen-juan，HUANG Hai-bin 2011, 30(6): 1420-1424.  DOI: 10.3969/j.issn.1674-0696.2011.06.38 Abstract ( )   PDF (315KB) ( )   A mathematical driver model is given in the spatial equation form，which takes into account the previewed information of the path． Optimal control method is applied to the“human-vehicle-road”control system with the proposed driver model and a kinematic vehicle model． Exponential stability conditions for the closed-loop control system is obtained． By the driver model，kinematic model and vehicle stability control system combination，with optimal control theory method， analysis based on the model of“human-vehicle-road”index of closed-loop control system stability condition． The driver model is simulated under MATALB/Simulink． The simulation results validate the driver model and evaluate the effect ofthe previewed distance on the vehicle stability control． The results show that the system with longer preview is easier to be stabilized． References | Related Articles | Metrics

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Evaluation Methods of Automobile Intelligent Design Based on AHP LIU De-fang，WU Hong-pan，WANG Bin，ZHOU Lin-zhen 2011, 30(6): 1425-1428.  DOI: 10.3969/j.issn.1674-0696.2011.06.39 Abstract ( )   PDF (210KB) ( )   With the application of automobile intelligent design system，it is inevitable that a large number of outdated and redundant knowledge are accumulated in the knowledge base． In this case，the efficiency of the design knowledge reuse is affected seriously． In order to improve the accuracy of design knowledge evaluation，AHP is introduced into assessment system of automobile intelligent design knowledge; the corresponding index system is designed; and the evaluation process is studied． Knowledge base of automobile intelligent design system has been optimized to improve quality and efficiency of intelligent design by effective evaluation of design． References | Related Articles | Metrics

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Improvement of MIPv6 Protocol Based on Elimination and Renewal Mechanism Hu Qing-gui 2011, 30(6): 1429-1434.  DOI: 10.3969/j.issn.1674-0696.2011.06.40 Abstract ( )   PDF (465KB) ( )   Firstly，MIPv6 Protocol is analyzed．And its shortage is introduced．Secondly，the new Protocol is put forward．In order to avoid low network performance，in the new protocol，the region accumulation time is adopted to determ ine which could be the home address and the home agent，the dynamic bufer table is adopted to achieve that goa1．Then，the perform- anee of the new protocol is simulated with OPNET software，which shows the new protocol could enhance the network performanee． For example，the average response time of the client object is 0.003 s in the new protocol，but in the old proto- col，it is 0.007 s． References | Related Articles | Metrics